Study On The Size Distribution And Bioavailability Of Particulate Matters

Atmospheric particles can carry many toxic and harmful components,they will have a direct negative impact on the human body.The study of exposure error has become an important research direction in the field of atmospheric research.This research studied the particle size distribution and composition of different particle size particles,which can contribute to the further analyze on the environmental toxicology and transformation of atmospheric particulate matters.It can provide practical guidance for air pollution.Scanning electron microscopey?SEM?and X-ray energy dispersive spectroscopy?EDS?were used to investigate the individual particle morphology and the chemical composition.Studies showed that PM_1.1-4.7 was the main component of indoor and outdoor particulate matter.The total concentration of indoor respirable particulate matter was only 44%of the outdoors,at the same level of contamination;The level of air pollution had a little effect on the percentage distribution of outdoor PM_4.7-10 and PM_1.1.PM_1.1 was the main components of outdoor PM_2.1.The total concentration of indoor particulate matters was only 44%of the outdoors,at the same level of contamination.Outdoor the content of C account for much higher proportion than that of indoor.The aggregated soots were the main components of the outdoor particles.The percentages of Al,Ca,Fe in the indoor particles were higher than the outdoors.The indoor PMs were compose of soot aggregates,fly ash and mineral particles.The mass concentration distribution of TSP,PM10 and PM2.5 in indoor and outdoor air was analyzed by using medium flow sampler.The results showed that indoor air pollution was mainly affected by indoor sources.On the basis of comparative study of the indoor and outdoor particles size distribution,Further study measured the distribution of typical elements in the form of particles,and an assessment of its bioavailability.Arsenic was a typical toxic element in atmospheric particulates.Research indicated that arsenic can be significantly enriched in the atmospheric particulate matters,and there were more serious arsenic contamination in northern cities.The arsenic morphology in the particles was distinguished by stepwise sequential extraction,and divided it into five species of different environmental activity.The results showed that there were significant differences in the distribution of different species of As in the indoor and outdoor,but the non-specific adsorbed state As was the main component.The arsenic in the particles have high bioavailability and environmental migration ability.The study have a positive reference value for the assessment of environmental effects of particulate matters.